High-pressure process to produce GaN crystals

Abstract

High melt temperature and thermal decomposition prevent the use of standard bulk semiconductor crystal growth processes for the production of GaN. We have employed a hydrostatic pressure system to grow GaN crystals. An ultrahigh pressure, high temperature process was developed using a solid-phase nitrogen source to form GaN crystals in a Ga metal melt. Using a thermal gradient diffusion process, in which nitrogen dissolves in the high temperature region of the metal melt and diffuses to the lower temperature, lower solubility region, high quality crystals up to ∼1 mm in size were formed, as determined by scanning electron microscopy, x-ray diffraction, and micro-Raman analysis.